Heating metal pot



G. J. HAGAN.

HEATING METAL POT. APPLICATION FILED SEPT.29, 192].

1,486,247. Patented Nov. 21, 1922 G. J. HAGAN.

HEATING METAL POT. APPLICATION FILE!) SEPT, 29, I921.

1,436,247. Patented Nov. 1922.

2 SHEETS- T 2.

Patented Nov. 21, 1922.

GEORGE J. HAGA N, OI PITTSBURGH, PENNSYLVANIA.

HEATING METAL POT.

Application filed September 29, 1921. Serial No. 504,202.

To all whom it may concern:

Be it known that I, Gnonon J. HAGAN, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvan a, a

citizen of the United States, have invented or discovered certain new and useful Improvements in Heating Metal Pots, of which improvements the following is a specification.

The invention described herein relates to certain improvements in coating metal sheets, the improvements being especially applicable to tmning sheets or galvanizing sheets.

It is desirable to maintain the molten metal in tinning pots at a certain predetermined temperature in order to ensure a uniform thickness and quality of coating.

The rate of movement of the sheets through the bath islargely determined by the temperature and having been fixed can:

be easily maintained as the sheets are moved through the molten bath by positively driven rolls, but as a solid fuel, as coal, is generally employed for melting and maintaining the metal in a molten condition, the maintenance of a uniform temperature is diflicult. The object of the invention described herein is to provide for the employment of auxiliary means for heating the metal, the heat applied by such means being variable by and in accordance with changes in the temperature of the metal bath. The invention is hereinafter more fully described and claimed.

In the accompanying drawings forming a part of this specification, Fig.- 1 is a sectional elevation of a tin pot having my improvement combined therewith, and Fig. 2 is a similar view having a modification in the form of auxiliary heaters.

in the practice of the invention the tin pot 1 is arranged above or in any suitable relation to the furnaceil in which any suitable fuel as coal, coke, etc., is burned, to melt the metal and to maintain it at a temperature preferably a little below that required for coating. In order to bring the metal to and maintain it at the desired temperature, an auxiliary heating means is employed which should be of such character that the heat generated thereby may be closely regulated by or in accordance with changes in the temperature of the molten metal. In the embodiment of the invention shown in Fig. 1, a submersible electric heater having two heating coils is employed as an auxiliary heater 3, said heater being controlled by a thermo-couple 4, operating through suitable circuit-changing device 5, solenoids 9, 11, 13, 14, and switches 10 and 12. On a change of voltage in the circuit of the thermo-couple due to changes in the temperature of the bath, the finger B will be shifted to open one circuit and close another, dependent upon the direction of change of temperature. The regulating mechanism is so constructed and adjusted that when the bath is at the desired temperature the finger 8 of the circuit changer will be between the pairs of contacts 6 and c. If the temperature of the bath falls, the finger'will contact with the pins of pair 0, closing the circuit through coil of solenoid 9, whereby switch 10 will be operated to close circuit through one of the heating elements. If the temperature continues to fall, solenoid 11 will be 0 erated to open switch 12 in the circuit of the other heating element. If, however, the temperature should rise from normal, the finger 8 will be shifted to contact with the pair of pins 6 closing circuit through coil of solenoid 13 which will thereupon operate to shift switch to open circuit through one of the'heating elements. A further rise of temperature will be followed by the opening of the circuit through the other heating element.

It will be understood that the electric heater is not intended to melt and maintain the bath in a molten condition, but to operate as auxiliary to the furnace and maintain automaticall' a suitable uniform temperature in the batli.

The auxiliary heater may be arranged within the bath as shown in Fig. 1, or may be so located outside of the pot as to heat one or more of the'side walls of the pot as shown in Fig. 2;

In the practice of the invention the operator will regulate combustionrin the furnace so as to heat the metal to a temperature slightly below that desired and depend upon the electric heater to furnish the additional heat required to raise the metal to the desired. temperature. As previously stated, the heating efl'ectobtained from combustion alone varies over a considerable range. ture value to be obtained from combustion, it is necessary to choose a temperature suf- Therefore in setting the temperafuel is employed, or where a liquid or gaseous fuel is employed, by shifting the valve controlling the supply to the furnace. In

the construction shown, a damper 19 regulating the supply of air to the furnace is connected by any suitable means, such for example as the cord 15, passing around pulleys 16 to the armature of a solenoid which is included in the circuit having contact points d and adapted to be closed' by the action of the thermo-couple when the temperature of the bath rises above the desired value. On the closing of the circuit, through this solenoid by the finger 8, the armature will be shifted to close the damper. As soon as the temperature drops and the finger passes over or ofi of these contact points, the damper will be opened either by a weight connected to the cord as shown, or by other suitable means.

ll claim herein as my invention:

1. The combination of a melting pot, a

1 ,aeaaa? furnace for the combustion of fuel whereby the metal in the pot is raised approximately to the desired temperature and an automatically controlled heater for maintaining the metal at the desired temperature.

2. The combination of a melting pot, a furnace for the combustion of fuel whereby the metal in the pot is raised approximately to the desired temperature, and an auxiliar heater controlled by and in accordance with changes in the temperature of the molten metal for maintaining the latter at the desired temperature.

3. The combination of a melting pot, a

furnace for the combustion of fuel for raising the metal in the pot approximately to the desired temperature, an electric heater supplementing the heating effect due to combustion in the furnace, and a thermostat subject to the heat of the molten metal for regulating the electric heater.

4. The combination of a melting pot, a furnace for the combustion of fuel whereby the metal in the pot is raised approximately to the desired temperature, an automatically controlled heater for maintaining the metal at the desired temperature, and means whereby the rate of combustion in the furnace may be regulated.

In testimony whereof, I have hereunto set my hand.

GEORGE J. HAGAN. 

